Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven-gill slits on the sides of the head, and pectoral fins that are not fused to the head.
Sharks are amazing fish that have been around since long before the dinosaurs existed. They live in waters worldwide, in every ocean, and even in some rivers and lakes.
Unlike bony fish, sharks have no bones; their skeleton is made of cartilage, a tough, fibrous substance that is not nearly as hard as bone.
Quick Facts About Sharks For Kids
- In some form, sharks have been around for about 400 million years.
- Sharks are the top predators of the ocean’s natural food chain.
- Sharks live for 20 – 30 years (In the wild)
- Sharks can swim up to 31 mph In Short Bursts
- Even before dinosaurs roamed the earth, sharks hunted through the oceans!
- There are over 400 types of sharks — they range in size from 6 inches to 45 feet.
- Sharks have the most powerful jaws on the planet.
- A shark bites with its lower jaw first and then it’s upper.
- Each type of shark has a different shaped tooth depending on its diet.
- A shark may grow and use over 20,000 teeth in its lifetime!
- Almost all sharks are “carnivores” or meat-eaters.
- Their skeleton is made of cartilage instead of bone, which allows greater flexibility.
- Their skin is made of denticles instead of ordinary fish scales.
- Two-thirds of a shark’s brain is dedicated to its keenest sense — smell.
- Some sharks have eyes similar to a cat. This allows the shark to hunt in clear seas or murky water.
- Sharks can feel vibrations in the water using the line of a canal that goes from its head to its tail.
- Sharks have a sensory organ called the “ampullae of Lorenzini,” which they use to “feel” the electrical field coming from their prey.
Types of Sharks
Bigeye Sixgill Shark
Blacktip Reef Shark
Bluntnose Sixgill Shark
Broad nose Sevengill Shark
Bronze Whaler Shark
Burmese Bamboo Shark
Caribbean Reef Shark
Galapagos Bullhead Shark
Gray Reef Shark
Great Hammerhead Shark
Great White Shark
Leafscale Gulper Shark
Pacific Sleeper Shark
Port Jackson Shark
Portuguese Dogfish Shark
Prickly Dogfish Shark
Sailfin Rough Shark
Scalloped Hammerhead Shark
Sharpnose Sevengill Shark
Shortfin Mako Shark
Whitetip Reef Shark
Zebra Bullhead Shark
10 Interesting Shark Facts
Sharks have always fascinated people, whether from fright, interest, or curiosity. So here are 10 fun and weird facts, in no particular order, about sharks.
1. In one form or another, the shark has been around for around 400 million years. Sharks, which belong to the class Chondrichthyes, roamed the earth before the dinosaurs and have not evolved for the past 150 million years. The smallest shark, the dwarf lantern shark, is only 6.7 inches long and eats shrimp and small fish. The largest shark, the whale shark, is 65 feet long, weighs around 75,000 pounds, and eats plankton.
2. Sharks do not have a single bone in their bodies. Their skeleton is made of cartilage, like a human ear, and connective tissue. Flexible cartilage has half bone density, which saves energy and weighs a fraction of what it would if it were bone. Because sharks do not have a rib cage, a shark on land would be crushed under its own weight. The head of a hammerhead shark is soft at birth to not get stuck in the birth canal.
3. Wasps and bees kill more people than sharks do. Around 100 people die from the stings of wasps or bees every year, while only 6 people are killed by sharks every year. There are only around 25 sharks (out of 400 species) that are known to attack people. On the other hand, people kill thousands of sharks every year for food, skins, oil, and sport. Shark skins are used to make products such as boots, belts, and purses. Shark steaks are eaten in many countries, including America, where the Mako shark is preferred. The very first account of an attack by a shark was found in Herodotus around the year 450 BC. Interestingly, up to 90% of shark attacks involved men.
4. Sharks shed teeth. Sharks have around 45 teeth with 7 rows of teeth, for replacement, behind them. When a shark loses or breaks a tooth, it only takes a day for a replacement tooth to takes its place. Sharks go through over 30,000 teeth in their life, with each new tooth coming in larger (this is why the older a shark is, the scarier it looks). Sharks have mighty jaws (in fact, they have the most powerful jaws on earth). Carnivores bite first with their lower jaw and then their upper jaw. To tear meat, sharks toss their heads back and forth and then swallow the meat whole.
5. Three of the largest sharks are the gentlest. The whale shark, the basking shark, and the megamouth shark live off plankton. These sharks swim, holding their mouths open, straining the tiny plankton with gill rakers located at the back of their throats.
6. Vitamin A used to come from shark liver oil. A basking shark can have a liver that weighs more than 1,800 pounds and can hold around 600 gallons of liver oil. The liver is the shark’s largest organ; it can be up to 25% of its total weight. A shark’s liver helps keep them afloat.
7. The megamouth shark has a mouth that can reach 3 feet across. These sharks, which were only recently discovered in 1976, are about 16 feet long. Only 50 megamouths have been seen, and they are considered a rare species. Because it is so rare, it has its own classification; Megachasmidae. The megamouth is ovoviviparous; this means that the baby sharks develop in eggs.
8. New Zealand’s swell shark barks like a dog. The swell shark pumps water into its stomach, causing it to swell. This makes it hard to pull the swell shark out from between rocks. It also makes it hard for bigger fish to eat it. The egg case of the swell shark resembles a drawstring purse and is called a mermaid’s purse.
9. Odd things have been found inside sharks. Some of the things that have been found inside the stomach of a shark include a bottle of wine, a suit of armor, a torpedo, chairs, and half of a horse. Most sharks swallow their food whole. Although some sharks will eat just about anything, most sharks rarely stray from their prey items. The cookiecutter shark slices out the flesh from larger prey. They are thought to attach themselves to their prey, make a tight seal with their lips, and twist their bodies quickly to tear off the flesh. Whitetip reef sharks hunt and eat in packs. Many sharks can reverse their stomachs (turn them inside out) to dispose of undesired content.
10. The Great White is the largest fish caught on a rod and reel. The Great White was 17 feet long and weighed 2,664 pounds. The largest Great White ever caught (off the coast of Prince Edward Island, was over 20 feet long. The Great White is the sea’s largest predatory fish and lives along the coasts of every continent except for Antarctica. The Great White, which is not actually all white and may have dark blue, brown, gray, or black on its back, can live for around 25 years. Their usual prey is sealed, and when they attack a person, which is rare, they thought the person was a seal. More than 70% of the victims of Great White attacks survive because the shark realizes that it has caught a human and does not finish the meal.